This invention relates to power saws of the type comprising a table mounting a saw assembly having a motor driven blade adapted to cut workpieces positioned on the table. Such saws usually have a fence mounted on the table in the form of two aligned fence members which support and position the rear of the workpiece.
A gap between the fence members allows passage of the blade during cutting of the workpiece and it is desirable for this gap to be closely aligned with the passage of the blade so that splintering of the rear of the workpiece, as the blade emerges therefrom, is minimised.
Where the saw is not capable of making mitre or bevel cuts, the fence members can be fixed in the appropriate position. Where, however, mitre cuts and/or bevel cuts are to be made, the fence members are usually adjustable so that their optimum position can be obtained. This is normally achieved by first adjusting the saw to make the requisite mitre and/or bevel cut and then bringing the blade into its cutting position without the workpiece in place. The fence members are then adjusted with respect to the blade. However this is not always easy, firstly because the saw assembly usually needs to be held in its cutting position against the action of a restoring force tending it towards its rest position, and secondly, in this position, the bulk of the saw assembly gets in the way of convenient and easy adjustment of the fence members and usually restricts vision of the area around the blade.
Another problem with such saws is that it is not always easy to gauge exactly where the blade will strike the workpiece during cutting, particularly when making mitre or bevel cuts, and so correct positioning of the workpiece on the table cannot be assured. Usually the workpiece is positioned approximately correct and then the blade moved towards the workpiece without starting the motor. The point where the blade will strike the workpiece can then be seen and final adjustment of the workpiece can be effected. Again, however, this is not always so easy and for the same reasons as mentioned above. On top of those is also the problem that with a circular saw blade it will always only touch the workpiece at a point (unless the workpiece has a concave surface corresponding to edge of blade) and moreover that edge is toothed and so the line of its cut is sometimes quite difficult to gauge.